Grinding-machine for beveling the edges of eyeglass-lenses and other pieces



H. J. BIRCHALLI GRINDING MACHINE FOR BEVELING THE EDGES 0F EYEGLASS LENSES AND OTHER PIECES. 'AIILICATION FILED 050.30.1919.

' Patented Jan. 11, 1931.

4 SHEETS-SHEET I H. 1. BIRCHALL.

GRINDING MACHINE FOR BEVELING THE EDGES 0F EYEGLASS LENSES AND OTHER PIECES.

APPLICATION FILED DEC-30.1919- Patented Jan. 11, 1921.

4 SHEET$-SHEET 3 H41. BI-RCHALL. v GRINDING MACHINE FOR BEVELING THE EDGES 0F EYEGLASS LENSES AND OTHER PIECES.

APPLICATION FILED DEC.30, 1919.

1 365348, mama Jan; 11,1921.

4 SHEETSSHEET 4- UNITED STATES PATENT OFFICE.

HENRY J AMES BIRCHALL, OF BIRMINGHAM, ElNG-LAND.

GRINDING-MACHINE FOR BEVELING THE EDGES 0F EYEGLASS-LENSIf-S AND OTHER PIECES;

Specification of Letters Patent.

Patented Jan. 11, 1921.

Application filed December 30, 1919. Serial No. 348,277.

To (1% whom it may] concern: 4

Be it known that I HENRY JAMns Bmorr- ALL, subject of the king of Great, Britain, residing at 23 Victoria road, Acocks Green, Birmingham, England, formerly v of 7 8 heelwright road, Erdington, near Birminghain, England, have invented certain new and useful Improvements in Grinding- Machines for Beveling the Edges ofEyeglass-Lenses and other Pieces, of which the following is a specification. I t t The invention provides. the hereinafter described and claimed improved grinding machine for double, or V beveling the edges of eye-glass lenses and other pieces.

The type of machine to which the inven tion relates is one in which the lens or piece to be beveled is separately revolved between the opposed peripheries of two grinding stones which in addition to, revolving are moved, by the effect of weights under control of a formeiglto advance and retire them as they grind the lens or piece to the shape of the former. Said former revolves with the lens or piece onv a shaft directed obliquely between the grinding stones, the I one grinding stone grinding the one bevel on the lens edge, and the other grinding stone simultaneously grinding the other bevel on said edge. I

In a grinding machineof thistypethe invention combines an arrangement whereby the axial position of the former on the shaft carrying it can be adjusted relative to the thickness of lens or glass piece held, so

that the apex of the Vbeveling of any thickness of lens shall always be in the center of the lens thickness. This relative adjustment may be made by. hand through micrometer-like gear operating between a clamping means for the lensand a carrier for the former;. but more particularly the invention arranges so that said relative adjustmentis automatically madeby the act of clamping the lens inposition for grinding. a The lens is gripped between the op; posed ends of a divided shaft tohold it in' the machine,: and one 9f said endsl is, fixed except for volution and the other endmovable axially in addition to revolution, and the former is mounted over a shaft portion of this movable end, and geared to it and to a hand wheel, device, by ,screw gearing, so that the position of the former is changed to an extent half the difference in the thickness oflens gripped. The ha nd wheel gear automatlcally movesout of action when released, so that. the clamping of the lenscan not he accidentally disturbed. Followers connect the carrier frames of the grinding stone with the former so that combined with the ,Weights, I. aforesaid, for moving said frames the grinding" stones, except for revolution, are entirely under the control of the former, particularly for the whole of the finish of the grinding which is to exactsize and shape.

Theframes carrying the grinding stones partly in side elevationandpartly in sec- I tion, of the grinding stones) their carrying frames, and the means for moving them and for tension ngthe r driving belt...

The bed or table of thamachineisrepresented at a, same providing a-generalucan rier for substantially mounting the. whole of the parts of-the machine and beingitself in anyway suitably supported from legs or upr1ght's, not shown.

The ,two grinding stones are ate and- (Z each being revolubly, fitted 'to a carrier frame 6, movable in a straightline between guid ing rails 67, c and within a bearing, efl rigidly secured on the table The spindles .of the grinding stones revolve in bearings 6 e of ,theframes, and grooved pulleys e are mounted thereonxto drive the two stones together byan endless belt 7 which passes around the two pulleys, around. the driving pulley f and around a tensioning pulley f whose bearings slide in guides f, of the table and are spring pressed, at i to automatically tighten the belt. The fore-part of each framee rides on the rails 03, e by wheels a depending from said frame each side, to make the straight line fmovement of the frame antifrictional. The rear part of the frame rides quite freely through the bearing 6 and at its end, 6, is jointedly connected with a first-order lever g fulcrumed at g and weight influenced on its arm 9 the position of the weight g on said arm being adjustable to determine the cut of the stones on the lens being ground. Each stone is similarly mounted, moved and revolved and the peripheries of the two stones are opposed and together operative upon the lens which is positioned for grinding between said peripheries. Each frame 6 is fitted with a follower h which after being set on said frame in relation to the former connects said former with the frames and moves said frames from the rotation of the former.

The lens 2' to be V beveled is securely held while operated upon with its thickness between the opposed ends f, 7' of a divided shaft 7' which is slowly and uniformly revolved while obliquely disposed between the opposed peripheries of the two grinding stones.

The opposed end j except for revolution is immovable, the shaft portion carrying it being mounted and revolved in the bearing provided at 76 with a thrust abutment, and driven from an undershaft 70 revolved from a toothed wheel 7% by toothed gear is", 70 the toothed wheel 70 being in any way suitably driven. The undershaft 70 has bearings at 76 k on the frame a, and at its opposite end, by gear wheels Z2 70 twins to the ones 76 7c drives the end j of the divided shaft j in the manner hereinafter described, so that said shaft j, although divided, revolves as one shaft at all times.

The opposed end 7' aforesaid, is movable axially of the shaft to clamp different thicknesses of lenses 2' between the opposed ends 7' 7. The shaft portion 7' carrying the end 7' indirectly forms a carrier for a former Z which is interchangeably mounted upon a sleeve m surrounding the shaft portion f to always revolve therewith but to be independently slidable upon said shaft portion y' to adjust the axial position of the former Z upon the shaft in relation to the thickness of lens 2' held between the opposed ends j j The shaft portion j extends inwardly to f, and is internally screwthreaded at j for the engagement of the screw-threaded shank n of an axially arranged revoluble plug it which is additionally externally screw-threaded at n to engage the screw-threaded bore m of the sleeve m. The gear wheel is is applied to a second sleeve 0 within which the sleeve on is slidably fitted, and which sleeve 0 is the main revolving part applied to the stationary bearing 9 of this shaft portion 7'*. The revolving plug a is independently slidable within the second sleeve 0, is rotated independently of said second sleeve, and its screw-threaded engagements with the shaft portion i and the sleeve m are differential and so that when the opposed ends j i are separated 1/16 of an inch the axial position of the former Z is changed 1/32 of an inch in the same direction as the end j moves, to do which the pitch of the screw-threads 92 m is half the pitch of the screw-threads n 9'. The plug n is maintained axially in one direction by the pressure of a coil spring 11, operating between a collar of the plug, and indirectly, the end of the second sleeve 0, for instance, against the stop nut a The sleeve m and the second sleeve 0 are revolubly connected by a key 7', and the sleeve on and the shaft portion 7' are revolubly connected by the key 1.

Applied to the plug n is a hand-wheel gear 8 for revolving said plug. This gear rovides a shaft, 8 revolubly and slidably fitted to a stationary bearing, 8 and provided with a hand-wheel 8 The inner end of this shaft 8 slidably and revolubly fits a bore of the plug n, and carries a key 8 for engagement with a gap n of the plug a when said plug is to be revolved from the hand-wheel s, the engagement being brought about by sliding the shaft 8 inwardly against the action of the coil spring, 8, suitably provided in the bearing, 8 between said bearing and a collar s of the shaft.

The former Z is clamped upon the sleeve m between an immovable collar Z of said sleeve and a clamping screw-threaded collar Z also carried by the sleeve, said former being made in halves to facilitate the positioning of it over the sleeve between the two collars. Said former always revolves with the shaft portion j and the sleeve m, but is independently slidable over said shaft portion with said sleeve m.

Fig. 2 shows a lens 2' clamped between the opposed ends j y' Assuming the thickness of this lens to be 3/16 of an inch and the former Z to be in the correct position in relation to the staggered peripheries of the grinding stones to accurately grind the lens with a central apex to the V beveling, and that the 3/16 of an inch lens is replaced by a lens of an inch in thickness, the end 8 of the shaft 3 is made to engage the gap a of the plug n, and then the hand-wheel is revolved anti-clockwise to revolve said plug and pull inwardly both the shaft portion 7' and the sleeve m, using the nut n as a pulling-in abutment. This separates the opposed ends 7' 7' so that the 9; of an inch lens can be put between them, after which the hand-wheel s is operated clockwise to cause the shaft portion 3' to clamp the lens between the opposed ends. When the lens is securely clamped the opposed ends will be l/l6 of an inch farther apart than when clamping the 3/16 lens, and the former Z will have been axially moved on the sleeve m 1/64 of an inch inwardly, that is to say half the difference of the thickness of lens gripped. Similarly when a thinner lens is gripped the former is advanced half the difference in the lens thickness.

The spring 11 operates immediately the grip of the lens between the ends 7' 7' takes place to effect the clamping pressure which is never above the power of the spring W.

The followers h are re-adjusted to the former Z when a different sized former is used, but for the change in the thickness of the lens held to be ground, the shifting of the former automatically controls the positions of the grinding stones relative to the edge of the lens being ground.

Having now described my invention What I claim and desire to secure by Letters Patent is 1. A grinding machine combining two grinding stones mounted on frames in staggered relation to advance and retire to and from each other, a divided shaft arranged between the peripheries of the two stones at an angle to said peripheries to carry and revolve the piece to be ground and a former, clamping devices for securing the piece between the ends of the divided shaft, means for adjusting the position of the former on the shaft relative to the thickness of piece held by the shaft, and means for connecting the grinding stone frames to the former so that they advance and retire under conrol of the former, substantially as described.

2. A grinding machine combining two grinding stones mounted on frames in staggered relation to advance and retire to and from each other, a divided shaft arranged between the peripheries of the two stones at an angle to said peripheries tocarry and revolve the piece to be ground and a former, means for securing the piece between the ends of the divided shaft and for simultaneously and automatically adjusting the position of the former on the shaft relative to the thickness of piece held, and means for connecting the grinding stone frames to the former so that they advance and retire under control of the former, substantially as described.

A grinding machine combining two grinding stones mounted on frames in staggered relation to advance and retire to and from each other, a divided shaft arranged between the peripheries of the two stones at an angle to said peripheries to carry and revolve the piece to be ground and a former, means for securing the piece between the ends of the divided shaft in the form of differential screw devices which also automatically adjust the position of the former on the shaft relative to the thickness of piece held, and means for connecting the grinding stone frames to the former so that they advance and retire under control of the former, substantially as described.

a. A grinding machine combining two grinding stones mounted on frames in staggered relation to advance and retire to and from each other, a divided shaft arranged between the peripheries of the two stones at an angle to said peripheries to carry and revolve the piece to be ground and a former, one opposed end of said shaft being immovable except for revolution, and the other opposed end axially movable in addition to revolution, means for securing the piece between the opposed ends of the divided shaft and for automatically adjusting the position of the former on the shaft relative to' the thickness of the piece held, and means for connecting the grinding stone frames to the former so that they advance and retire under control of the former, substantially as described.

5. A grinding machine combining two stones mounted on frames in staggered re lation to advance and retire to and from each other, a divided shaft arranged between the peripheries of the two stones at an angle to said peripheries to carry and revolve the piece to be ground and a former, one opposed end of said shaft being immovable except for revolution and the other opposed end axially movable in addition to revolution, means for securing the piece between the opposed ends of the divided shaft and for automatically adjusting the position of the former on the shaft relative to the thickness of the piece held-, and means comprising adjustable followers and adjustable weight devices for connecting the grinding stone frames to the former so that they the former, substantially as described.

In testimony whereof I have hereunto set my hand in presence of two subscribing witnesses.

HENRY JAMES BIRGHALL.

Witnesses JOHN PHILLIPS FUnRY, G. H. GIFFoRD.

advance and retire under control of I 

